Construction worker's son feeling pinch of publishing industry slowdown. Studied biophysics at MIT while working for first U.S. computer magazine, Computers & Automation; made associate publisher by graduation. Founded International Data Group 1964; launched trade magazine Computerworld 3 years later. Now has more than 300 magazines, trade shows, 450 Web sites. Last year sales rose 6% to $3.2 billion. Gives away stock options to employees, despite having no desire to take IDG public. Company has invested $950 million in venture capital companies in China, $150 million in India, $100 million in Vietnam, $100 million in Korea. Created McGovern Institute for brain research at alma mater.